Usnea & Other Medicinal Lichens

Download a free booklet by Christopher Hobbs on medicinal lichens.

Lichens are organisms that are formed from a synthesis of an algae or cyanobacteria, or both, that form colonies within the mycelium or filaments of a fungus. Often considered a symbiotic relationship, each perhaps contributes something to the whole organism. The lichen is nature’s solar collector. The algae converts sunlight to sugar, upon which the fungus feeds, and the fungus acts as a matrix to support the algae, contributing minerals and protective compounds against bacterial pathogens called lichen acids. It turns out that lichen acids are phenolic acids that are highly inhibitory against a number of human pathogens, including Streptococcus and Staphylococcus. Thus lichen extracts have been used in traditional medicine for treating and preventing infections of the skin and upper respiratory tract. The lichen acids are very poorly absorbed from the gut and so cannot act effectively as systemic antibiotics, even though they are more potent than penicillin when in direct contact with strep and staph pathogens.